“Angelina is really upset, she didn’t think Brad would fight this hard for the kids – she thought he would roll over and she would get her way,” the insider revealed. “But Brad’s vowed to do everything in his power to gain as much custody of the kids as possible. He’s not going to just cave in and allow Angie to play her games.”

Jolie fought to gain full custody of the kids ever since she filed for divorce back in September. Despite Jolie’s attempt for custody, Pitt isn’t giving up without a fight.

“For some reason, Angelina through she would be able to cut Brad out of their lives for good, and she’s learning she can’t,” the insider added. “He’s their dad for heaven’s sake, he was the right to see them. Prepare yourselves, you haven’t seen anything yet – this divorce is about to get a whole lot nastier.”

Pitt and Jolie have not agreed to a visitation schedule. The World War Z star has only seen his kids only a handful of times since the split while Jolie has been secluding herself in a hotel in Bel Air.

“She comes in and out a back entrance and keeps a low profile,” an insider said of Jolie. “She appreciates the privacy the secluded hotel provides her and her family.”

According to The Sun, two of Jolie’s close advisors from Britain have been guiding the actress’ every move since the breakup. Jolie’s relationship with Chloe Dalton and Arminka Helic created a lot of problems in her marriage, especially once Brad Pitt couldn’t even talk to Jolie without them being present.

“At first he enjoyed having them around. But you could see, especially in the last year, he started to get more and more infuriated with them because they would never be out of the room,” an insider revealed. “Every time he went into a room and wanted to speak to Angelina, they’d be there in the background. And he could definitely see the change that was going on where they would constantly advise her.”

Jolie’s involvement with the women, who are high-ranking in the British government, has been well documented over the years. In fact, Jolie has allegedly been making a move to gain an important position in the U.N. and is relying on their advice to meet her career goals.

“I think their end game is to support Angelina and they don’t pay enough regard to the impact it will have on Brad’s life,” the source added. “Brad is despondent but being committed to his children and remains dedicated to the process.”

While Pitt continues to fight for joint custody, E! News reports that Jolie has made her first public appearance since the split. The Tomb Raider star was spotted leaving a Hotel Bel Air wearing a black dress and looking as solemn as ever.

According to Radar Online, Jolie looked skinnier than ever during the appearance. While she hasn’t released an official comment on the matter, the divorce is clearly taking a toll on her health.

For his part, Pitt recently walked the red carpet at the premiere of his new film, Allied. The actor took the time to converse with fans during the outing and told the media that he was thankful for all the support.

“It’s really sweet, everyone has been really kind out here,” he stated. “It’s really nice to have all the support.”

Tell us! Do you think Brad Pitt and Angelina Jolie should share custody of their six kids? Let us know in the comments section below.